The stated objectives of this research are to assess and develop procedures to enhance the capacity of adults with mild and moderate mental retardation (MR) to provide informed consent for therapeutic research, and to exert their rights to assent or dissent when surrogate consent is obtained. The project will have two phases, with the first designed to examine the understanding of basic elements of psychotropic treatment including the purpose and nature of the research, risks and benefits, voluntary nature of the participation, and right to withdraw without penalty. The project will also examine comprehension of the consent elements (e.g., goals, role of a scientist, nature of placebo conditions, etc). Consent capacity will also be evaluated within the four psycho-legal standards outlined by Appelbaum and Grisso (1988). In phase 1, persons with mild, moderate and "typical;" intelligence will be respond to a hypothetical vignette describing research utilizing a randomized control trial of a new medication to reduce aggressive behavior. In phase 2, the authors will use data generated from phase 1 to develop and evaluate three formats designed to improve the consent capacity of individuals with mild and moderate MR: 1) a picture book format, 2) a video format, and 3) a supported decision-making format. A significant other is also chosen by the subjects to aid in them during the three format presentations.